Methods of and apparatus for completing multiple zone wells



C. C. BROWN July 23, 1963 METHODS OF AND APPARATUS FOR COMPLETINGMULTIPLE ZONE WELLS 6 Sheets-Sheet 1 Filed April 16, 1958 INVENTOR F5.mm

c. c. BROWN 3,098,524 METHODS OF AND APPARATUS FOR COMPLETING MULTIPLEZONE WELLS July 23, 1963 6 Sheets-Sheet 2 Filed April 16y 1958 C/cero C.Brown INVENTOR ATTORNEY) C. C. BROWN July 23, 1963 METHODS OF ANDAPPARATUS FOR COMPLETING MULTIPLE ZONE WELLS Filed April 16, 1958 6Sheets-Sheet 3 C/cero C. 5/0 vvfl INVENTOR llllh July 23, 1963 FiledApril 16. 1958 C. C. BROWN METHODS OF AND APPARATUS FOR COMPLETINGMULTIPLE ZONE WELLS 6 Sheets-Sheet 4 50-0 Q m V Fm k i I 1 fh i 4/ F/ 7E s iii A A A wg 02? I" a \7. [q E l 5a K Z6a y K 29Q 7" J00 M .A

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METHODS OF AND APPARATUS FOR COMPLETING MULTIPLE ZONE WELLS Filed April16. 1958 6 Sheets-Sheet 5 C/cero C. Brow/7 INVENTOR ATTORNEY C. C. BROWNJuly 23, 1963 METHODS OF AND APPARATUS FOR COMPLETING MULTIPLE ZONEWELLS Filed April 16, 1958 e Sheets-Sheet s United States Patent3,98,524 METHODS OF AND APPARATUS FUR COM- PLETING MULTWLE ZONE WELLSCicero C. Brown, Houston, Tex., assignor to Brown (Bil Tools, Inc,Houston, Tex a corporation of Texas Filed Apr. 16, 1958, Ser. No.728,967 Claims. (Cl. 166-48) This invention relates to new and usefulimprovements in methods of and apparatus for completing multiple zonewells.

The invention disclosed herein is an improvement on the method andapparatus illustrated in my co-pending application, Serial No. 659,197,filed April 26, 1957, now Patent No. 2,991,833.

It is one object of this invention to provide an improved method andapparatus for completing multiple zone wells, wherein a plurality ofwell tubing strings may be landed in final position in the well headequipment prior to the setting of the Well packers which seal offbetween said formations and also wherein the well packers arehydraulically-actuated and are of the type in which the packing elementthereof is moved into sealing position by the application of an endwiseforce to said element.

An important object is to provide an improved well apparatus including aplurality of hydraulically-actuated packers mounted upon a firstproduction string, together with additional production strings extendingto and through certain of the packers to conduct well fluids from thevarious production zones which are separated by the packers, saidpackers being settable by pressure applied thereto from one or more ofthe production strings and being releasable by manipulation of the firstproduction string, whereby unsetting and removal of all packers may beaccomplished solely by means of said first production string.

Another object of the invention is to provide :an improved method oflowering a plurality of well packers and production strings into a wellbore wherein a first production string, a portion of the second stringand a trio of well packers are lowered simultaneously into position intothe well bore, after which the remaining portion of the second stringand a third production string are lowered and connected with theuppermost packer to establish the desired communication with the variousproducing formations.

Still another object of the invention is to provide an improved wellapparatus having hydnaulically-actuated packers for sealing off betweenproduction zones, which zones communicate with their respectiveproduction tubing strings; the apparatus including means whereby thepackers may be selectively set and properly tested by the application ofpressure through the various strings, thereby assuring that propersealing has been accomplished before the well is finally put onproduction.

Still another object is to provide an apparatus of the characterdescribed in which each packer, after being set, is maintained in setposition .without the necessity of holding pressure within therespective production strings, release of the pressure acting tomaintain the packers in set position being effected by manipulation ofonly one of the production strings.

A further object is to provide a well apparatus of the characterdescribed in which safety joint connections are properly positionedbetween the spaced packers so that in the event that the packers can notbe removed in a normal manner by the manipulation of one of theproduction strings, 1a disconnection may be made thereby permittingsubsequent removal of the packers by any other well-known means.

A particular object of the invention is to provide a well apparatus ofthe character described, wherein the packing element of each well packeris deformed into a set position by an endwise compressive force and alsowherein each packer is so arranged that the force applied to the packingelement to set the same is not transmitted to the production string onwhich the element is mounted, whereby stretching of said string duringsetting of the packer is avoided.

The construction designed to carry out the invention will be hereinafterdescribed, together with other features thereof.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and wherein:

FIGURE 1 is a schematic view illustrating the lowermost packer beingmoved downwardly within the well bore;

FIGURE 2 is a schematic view showing the intermediate and upper packersmounted on the first tubing string and also showing a portion of thesecond tubing string connecting the intermediate and upper packers andillustrating continued lowering of the apparatus within the well bore;

FIGURE 3 is a view similar to FIGURES 1 and 2 with the three packers insubstantially final elevation within the well bore;

FIGURE 4 is a similar View showing the remaining portion of the secondtubing string and the third tubing string in position and alsoschematically illustrating all three strings in final landed position inthe control head equipment;

FIGURE 5A is a view partly in section and partly in elevation of theupper end of the well bore showing the three tubing strings landed infinal position in the control head equipment; for the sake of clarity,the three production strings are shown as arranged in transversealignment although in actual practice said strings will be disposed atvarious radial points with respect to the axial center of the well bore;

FIGURE 5B is a continuation of FIGURE 5A showing the structural detailsof the upper packer;

FIGURE 5C is a continuation of FIGURE 5B showing the details of theconnections between the upper packer and the intermediate packer;

FIGURE 5D is a continuation of FIGURE 5C showing the structural detailsof the intermediate packer;

FIGURE SE is a continuation of FIGURE 5D illustrating the connectionbetween the intermediate packer and the lower packer;

FIGURE SP is a continuation of FIGURE 5B showing the structural detailsof the lower packer;

FIGURE 5G is a continuation of FIGURE 5F showing the lower extension ofthe first tubing string;

FIGURE 6 is a horizontal cross-sectional view taken on the line 6-6 ofFIGURE 5B;

FIGURE 7 is a horizontal cross-sectional view taken on the line 7-7 ofFIGURE 5B;

FIGURE 8 is an enlarged cross-sectional view of the check valveassembly;

FIGURE 9 is an isometric view of the clutch element which connects eachpiston of the packer assembly with the tubing string;

FIGURE 10 is an enlarged sectional view of the retrievable closure plugwhich may be employed to close flow through the tubing strings, and

FIGURE 11 is a horizontal cross-sectional view taken on the line 1111 ofFIGURE 5B.

In the drawings (FIGURES l to 4), the numeral 10 designates a well borehaving the usual well casing extending therethrough. The well bore isillustrated as traversing an upper producing formation or zone P1, a

. second or intermediate producing formation or zone P2,

and a third or lower producing formation or zone P3. The casing isformed with the usual perforations 12 pposite each producing zonewhereby the well fluids from that zone may enter the bore of the casing.

In order to produce the well fluids from each zone or formationindependently of the other zones or formations, it is necessary to sealor pack off each zone from the others and to establish communicationbetween each isolated zone and its respective production string or welltubing. FIGURE 4 illustrates a lower packer A positioned between thelower and intermediate zones, a second packer B located between theintermediate and the upper zones, and a third packer C located above theupper zone. A first production or tubing string T1 extends from thesurface through all three packers, A, B and C, and as will hereinafterappear, communicates with the lowermost zone or formation P3 to conductthe -well fluids from this formation to the surface. A second productionor tubing string T2 extends from the area below the intermediate packerB, then upwardly through the upper packer C and to the surface. A thirdproduction or tubing string T3 extends from the area below the upperpacker C and upwardly to the surface. As will be explained, all threetubing strings, T1, T2 and T3, having the packers connected and sealingtherewith in the manner hereinafter described, are landed in the controlhead equipment schematically illustrated in FIGURE 4 and designated bythe letter D. As shown in FIGURE 4, final landing of the strings in thecontrol head equip ment is made prior to the time that the packers A, Band C are moved into a set or sealing position within the wall of thewell casing. Thus, after landing of the three strings, it is possible tocirculate through any one or all of the strings and a free circulationaround all packer-s may be accomplished. Thereafter, by means ofhydraulic pressure, the packers A, B and C may be moved into sealing orset position, such pressure being applied through the bore or bores ofthe tubing strings. When the packers move into sealing or set position,they function to isolate the producing formations from each other and atthat time the lowermost formation or zone P3 is produced through thefirst tubing string T1 and the fluids from the intermediate formation orzone P2 are produced through the tubing string T2 and the fluids fromthe upper formation or zone P1 flow to the surface through tubing stringT3.

The present invention involves a novel method of lowering and finallysetting the packers as well as an improved method of removing saidpackers when such removal becomes necessary and FIGURES 1 to 4illustrate the manner in which said packers and strings are positionedWithin the well bore. Referring to FIGURE 1, the lower packer A isconnected to or mounted upon the lower portion of the first string T1and is lowered within the well by means of said tubing string apredetermined distance and lowering is halted when the packer B is to beconnected. The distance between packers A and B is in accordance withthe location and extent of the producing zones P3 and P2. Packer B isthen connected to or mounted upon the first tubing string T1, this beingaccomplished at the well surface and lowering is then continued.Thereafter, a tubular conductor or section T2a of the second tubingstring (FIGURE 2) is run into the well and connected to packer B. PackerC is then mounted upon or connected to the first tubing string T1 in themanner illustrated in FIGURE 2, and at this time another section T2-b ofthe second tubing string T2 is connected in place. The section TZ-b hasits upper end coupled to the lower end of packer C with its lower endsecured to a union coupling 13, which may be just beneath the upperpacker. The union is employed to make the connection between sectionsTZ-a and T2-b so that, in effect, the packers B and C are connectedtogether, not only by the first tubing string T1, but also by thecoupled sections TZ-a and T2-b of the second tubing string T2, whichcoupled sections form a tubular conductor extending between packers Band C.

Thereafter, this portion of the assembly is lowered as shown in FIGURE 3and lowering is continued until the packers A, B and C are located attheir proper elevations with respect to the producing formations orzones P1, P2 and P3, At this time the packers are not set and are not insealing engagement with the well casing 11.

Thereafter, the upper section T2-c of the second tubing string T2 islowered within the well bore and is coupled to the upper packer C and,as will be explained, such coupling establishes connnunication with thetubular conductors formed by the sections TZ-a and TZ-b of the stringT2. Following this the third tubing string T3 is run into the Wellindependently of the other strings and is coupled or connected to theuppermost packer C. All three strings, T1, T2 and T3, are then landed inthe control equipment in their final position and the well is thencompletely under control. However, at this point the packers A, B and Care not in sealing engagement with the well casing. This position of theparts of the apparatus is illustrated in FIGURE 4.

It will be evident that at this time a circulation may be effecteddownwardly through the first tubing string T1 and such circulation willpass upwardly around the lowermost packer A and may return upwardlythrough tubing T2; or a portion of the return may be through the llhlf dtubing string T3 since the circulation may pass around the outside ofthe unset packer B. The control head equipment D includes the usualoutlet 14 from the casing, which is controlled by valve 15 and, ifdesired, this valve may be opened so that circulation may be downwardlythrough one or more of the tubing strings T1, T2 or T3 with returnsbeing conducted from the casing through outlet 14. Similarly, ifdesired, circulation can be in a reverse direction. It is, therefore,possible to carry out any desired washing or circulating step with alltuhings in place, finally landed in the control head and prior to thetime that any of the packers are set.

As will be explained, the packers are constructed to be set by hydraulicpressure which is applied through one or more of the tubing strings. Bydropping a closure plug, generally indicated at E in FIGURE 4, Withinthe first tubing string T1 a pressure may be built up within the tubingstring and, as will be explained, such pressure may be utilized to setall three of the packers A, B and C. If the plug E is dropped into thesecond tubing string T2, pressuring up in tubing T2 may function to setthe intermediate packer B and the upper packer C. If it is desired toset only the upper packer C, the plug E may be dropped within tubing T3and pressure applied through this tubing will set the uppermost packer.The apparatus is thus extremely versatile and the particular packer orpackers which are set and the order in which they are set is subject tothe particular well conditions. The arrangement also makes it possibleto set the packer and then test the same to be certain that it is insealing engagement with the well casing.

For example, plug E may be lowered in tubing T3 and pressure applied toset the upper packer C. Then by circulating downwardly through tubing T1and upwardly around packers A and B with return through tubing T2, it ispossible to test to be sure that the packer C has been properly set.This circulation may also accomplish a washing operation which clearsthe bore below the second packer of mud and washes the face of theproducing formations. If the plug E is removed from the tubing T3 afterthe upper packer C is set, then downward circulation through tubing T3and return through tubing T1 accomplishes a washing of that portion ofthe well bore below the upper packer C. Thereafter, packer B may be setby dropping a plug through the second tubing string I72. A pressure testfrom above packer B may be made by circulating downwardly through tubingT3 and a test below said packer may be effected by circulat ingdownwardly through the first tubing string T1. Thereafter, the lowerpacker A may be set, and by proper application of pressure throughtubing T2 or tubing T1, packer may :be tested for sealing efiiciency.

After all of the packers are set, the plugs E are, of course, removedand flow from each producing formation is conducted to the surfacethrough its respective tubing string.

As will be explained, release and unsetting of the packers and removalthereof may be eifected by a manipulation of the first tubing string Tl.This is one of the features of the invention since all three packer-smay be released simultaneously and removed from the well bore by thesingle production string. In such case the upper section T2-C of thesecond production string T2 and the third production string T3 are firstremoved after which the first string T1 is manipulated and removed. If,for some reason, simultaneous release and removal of all three packerscan not be effected by the first string, the apparatus is so arranged inthe well that the upper packer may first be released and then by meansof a safety joint F below said first packer, a disconnection of theupper packer and upper section of the first tubing from the remainder ofsaid first string and the lower packers may be accomplished. Thereafter,a suitable overshot or similar tool may be engaged with that portion ofstring T1 still remaining in the Well to remove the intermediate packer.B and the lowermost packer A. If both of these packers will not releaseon the same operation, another safety joint G is provided betweenpackers B and A so that another section of string T1 and packer B may beindependently removed. Thereafter the final section B of string T1 withthe lower packer may be removed.

Although the particular construction of the individual packers issubject to variation, insofar as the method of running, completing,setting of the packers and subsequently removing said packers isconcerned, it is preferred to employ hydraulically-actuated wellpackers, each of which have .an elastic packing element which isdeformable into sealing position by endwise compression or force. Thistype of packer is distinguished from the so-called balloon type whereinpressure is applied to the interior of the element. The drawingsillustrate the preferred type of well packers.

FIGURES 5A to 5G illlustrate the complete apparatus firom control headequipment D to the lower end of the well bore and it is noted that thethree tubing strings are shown as in transverse alignment; however, inactual practice the strings would not be in such alignment and are shownin this manner for illustrative purposes only. Actually, the threestrings are spaced at various radial positions with respect to the axisof the well bore as shown in FIGURE 7.

Referring to FIGURE 5A, this figure illustrates the three tubing stringsT1, T2 and T3 suspended from a tubing head 20 which forms part of thecontrol head equipment D. Each tubing string has a suitable controlvalve 21 connected therein whereby flow through each string may becontrolled. The valved outlet 14 is mounted in the body portion 22 ofthe tubing head. The tubing head is, of course, supported on the upperend of the well casing 11.

The first tubing string T1 extends downwardly through all three packersC, B and A and the other two strings T2 and T3 have connection with theuppermost packer C as is illustrated in FIGURE 5B. The packer C includesa main body 23 having an axial bore 24 extending comletely therethroughand the first tubing string T1 extends entirely through this bore. Atubular mandrel or pipe section 25 has its upper end connected to thelower end of the bore 24 and extends downwardly therefrom, the

bore of the mandrel 25 forming a continuation of the bore 24.Surrounding the mandrel 25 and disposed below the body 23 is an elasticpacking element 26 having confining rings 27 and 28 engaged with itsupper and lower ends. Below the elastic packing element and also mountedon the mandrel 25 is a slip expander cone 29 having an outer taperedsurface 30. The cone 29 is normallysupported on a ring or shoulder 31secured to the exterior of the mandrel 25.

Adapted to co-act with the expander cone 29 are a plurality of grippingslips 32 which are mounted for radial movement in an outward directionwhen the cone and slips are moved with respect to each other. The lowerend of each slip is formed with a T-shaped lug 3G engaged in acomplementary recess 34- formed in the up per end of a cylinder member35. The cylinder member surrounds the lower portion of the tubularsection or mandrel 25 and has a head 36 at its upper end. The cyl inderencircles a piston body 37 which, in turn, is at tached to the lower endof the tubular mandrel 25. An angular fluid passage 38 having aback-check valve 39 is formed in the piston and the lower end of thepassage communicates with the space between the tubing T1 and the boreof the piston 37. The tubing T1 is provided with a radial port 40 andwhen fluid pressure is applied to the interior of the tubing T1, suchpressure may pass the check valve 39 and may enter the space indicatedat 41 between the upper end of the piston and the lower surface of thehead 36 of the cylinder upwardly with respect to the piston and withrespect to the tubular mandrel 25 as well as the parts carried by suchmandrel.

The cylinder is slidable axially on the piston 37 and a shear pin 1'44normally connects the cylinder to the piston until a predeterminedpressure is applied between the piston and the cylinder.

The slips, piston and cylinder are normally in the position shown inFIGURE 5B, but when pressure is applied beneath the head 36 of thecylinder, the pin 144 is sheared and the piston is moved upwardly. Sincethe slips 32 are connected with the cylinder and since the expander coneis carried by the support 25, which is stationary at this time, theslips are moved upwardly into grip-ping engagement with the wall of thecasing. As soon as the slips engage, further upward movement of thecylinder is halted and the pressure within the space between head '36 ofthe cylinder and the piston will react in a downward direction againstthe piston. When this occurs, the piston 37 will be moved downwardlyrelative to the cylinder, slips and expander cone and through thetubular support will apply downward force to the upper body 23. Suchdownward force will apply a downward pressure upon the upper end of theelastic packing element 26 and will effect a distortion of said elasticpacking element into sealing engagement with the wall of the wellcasing. Due to the back-check valve, the pressure will be trappedbetween the piston and the head 36 of the cylinder and will retain thepacking element and slips in set position even though pressure withinthe tubing string T1 is relieved.

In order to release the pressure so that the packing element and slipsmay be released, the tubing T1 is rotated, as will be explained, and ismoved upwardly with respect to the various parts of the packer Cassembly. Such upward movement will locate the port or opening 4% in thetubing T1 opposite a relief port 44 which extends through the tubularsupport 25 opposite the upper end of piston 67. Registration of ports 40and 44 will allow the pressure, which is trapped between the piston andthe head 36 of the cylinder, to be relieved through the interior of thetubing string T-l so that the slips may be returned to their originalposition with respect to the expander cone and applied pressure to thepacking element 26 will be relieved. At the same time that port 40 ismoved into registration with port 44 a reduced portion 45 on theexterior of tubing T1 will span the packing member'46 which normallyseals off around the tubing T1 to allow a bypass of fluid around thispacking so that pressures across the unit may be equalized. Theregistration of ports 40 and 44, together with the c'o-action of thereduced portion 45 with the packing member 46, provide a release meansfor effecting a release of the set packing element 26 and the grippingslips 32 to thereby release the packer C from set position.

In addition to the bore 24-, which is provided in the upper body 23 ofthe upper packer C, said body is formed with a second bore 47 whichreceives the lower end of the section T2c of the second tubing string.The lower end of this section of the second string is formed with a J-slot coupling 48 which co-acts with a connecting pin 49 formed withinthe bore 4-7. Thus, the upper section T2-c of the second tubing stringis detachably or releasably connected with the upper packer C.

A continuation of bore '47 entirely through the packer C is provided bya tubular pipesection 50 which extends through aligned openings in theelastic packing element 26, the expander 29, head 36 of cylinder 35 andthe piston 37.

The upper body 23 of the packer C is also formed with a third bore 51which is adapted to receive the lower end of the third tubing string T3.This third tubing string has its lower portion formed with a J-slotcoupling 52 engageable with a connecting pin 53 so that the third tubingstring may be releasably attached to the upper packer. The bore 51 ispreferably of a different diameter or size than the bore 47 and thetubings T2 and T3 are of different diameters so that when each of thesestrings is run independently and adapted to be attached in itsrespective bore, the proper tubing will set within the proper bore. Thebore 51 of the upper body 23 is continued by means of an elongate pipesection 54 which extends downwardly through aligned passages provided inthe elastic packing element 26, expander 29, cylinder head 36 and piston37; obviously, this pipe section forms a continuation of the tubingstring T3 and, as shown in FIGURE C, this section terminates just belowthe upper packer C. Within the lower portion of the pipe section orconductor 54 is an annular seat 55 which is adapted to receive one ofthe removable plugs B when it is desired to pressure up within the thirdtubing string T3.

As previously described, the upper packer C may be set by applying fluidpressure from the interior of the first tubing string T1. However, itmight be desirable to actuate the packer by fluid pressure from withinthe tubing T3 and for this purpose an angular passage 56 (FIG- URE 5B)is provided. The passage is similar in construction to passage 38 andhas a back-check valve 57 mounted therein. The passage communicates withan opening or port 58 formed in the tubular conductor or pipe 54. Asimilar passage (not shown) is formed in the piston 37 and has its lowerend communicating with a port 58a provided in the tubular conductor 50which forms a part of the second tubing string T2. With this arrangementit is obvious that the packing element 26 and slips of the upper packermay be set by pressuring up through any one of the three tubing strings.Release of pressure, however, and unsetting of the packing element andslips of said packer is accomplished only by manipulating the firststring T1.

After extending through the upper packer C, the first tubing string T1extends downwardly below the upper packer and is connected thereto by aspecial clutch coupling 59 formed on a tubular extension 60 whichextension is secured to the piston 37 of the packer assembly.

The coupling 59 is of special construction and is provided, not only forthe purpose of coupling the packer C to the string T1, but also for thepurpose of permitting the endwise compressive force to be applied to thepacking element 26 Without transmitting the downward move-, ment of thepacking element, piston and mandrel 25, as caused by such compressiveforce, to the string T1;

with such arrangement, the hydraulic pressure which imparts the downwardmovement to the piston 37 and mandrel 25 and upper body 23 will notresult in stretching the tubing. Also, the co-operating parts of thecoupling may function as a jar, as will be explained.

The coupling 59 is illustrated in detail in FIGURE 9 and includes anupper body section 70 having a threaded pin '71 which connects to thetubular extension 60 depending from the piston 37. The body has fingerportions 72 which telescope upstanding fingers 73 of a lower section 74.The fingers are normally in the position shown in FIGURE 9 and areextended with respect to each other, being held so by shear pins 75. Thebore of the lower section 74 has the internal threads 61 which couple tothe tubing T1 and below said threads are additional comse couplingthreads 77 which subsequently co-act with coarse coupling threads 78 ofa coupling 79, the latter being also carried by tubing T1.

In the operation of the special coupling 59 the initial application ofpressure to the area between the piston 37 and the cylinder head 36 willresult in an upward movement of the cylinder to set the slips 30. Thenthe reactive force is in a down direction which would tend to move thepiston 37 downwardly as above explained. This results in shearing thepins 75 of coupling 59 and, thereafter, the piston 37 may movedownwardly the length of movement between fingers 72 and 73. Since thefingers 72 are also, in fact, connected with the piston and the fingers73 are connected with the tubing T1, the piston may undergo a downwardmovement sufficient to set the elastic packing element '26 withoutimparting the same movement to the tubing string T1. In this manner anystretch in the tubing, which might be caused by pressure application, iseliminated.

Below the coupling 79 is the safety joint F, said joint includingthreads 62 which have the same lead as the threads 61 of the coupling59.

When it is desired to release the packing element and slips of thepacker C, it is necessary to raise the tubing T1 with respect to thepacker. The threads 61 of coupling 59 are left-hand threads and byrotating the tubing T1 to the right, the threads 61 are disconnectedthereby permitting the tubing T1 to be raised with respect to the packerto place the ports 40 in registration with release ports 44. After thepressure between the piston and cylinder is relieved, it is desirable toreconnect the tubing T1 to the packer assembly and to accomplish this,the threads 78 of the coupling 79 are engaged with the threads 77 of thecoupling 59. The distance between coupling 59 and coupling 79 is suchthat suificient upward movement of the tubing T1 may be accomplished toeffect release of pressure and, thereafter, tubing T1 is reconnectedthrough said threads 77 and 78 to the upper packer C whereby the tubingT1 may be utilized to withdraw the packer from the well bore.

In the event it is necessary, the ends of the fingers 72 and 73 may beengaged with each other and then by taking tension on the tubing andthereafter rotating said tubing, an upward jarring blow will bedelivered to the extension 60 and mandrel 25 to assist in releasing thepacker.

As Will hereinafter appear, the manipulation of tubing T1 may alsoeffect a release of the intermediate packer B and the lowermost packerA. However, if the two lower packers do not release for one reason oranother, the continued rotation of tubing T1 will break out the threadsof the safety joint F and the upper packer may be withdrawn from thewell bore separately from the other packers.

The first tubing string T1 continues downwardly through the secondpacker as is illustrated in FIGURE 5D. The construction of theintermediate packer B is substantially the same as that of the upperpacker C except that it is provided with one bore 24a for the receptionof tubing T1 and a second bore 47a for the reception of the secondtubing string T2. Since tubing string T3 terminates just be low theupper packer, it is not necessary to provide a third bore through thepacker B.

Since the construction of the intermediate packer is substantially thesame as the upper packer, it is not believed necessary to describe thesame in detail. However, briefly, the intermediate packer includes anupper body 23a, a packing element 26a, an expander cone 2%, slips 30a, acylinder 35a having a head 36a and a piston 37a. The piston has anextension dila projecting downwardly therefrom and the special clutchcoupling 59 connects the tubing T1 with the packer B.

The piston 37a is formed with an angular port 38a having a back-checkvalve 39a. The angular port is adapted to communicate through an openingor port 40a provided in the tubing T1 with the bore of the tubingwhereby pressure within the tubing T1 may be introduced into the areabetween the piston 37a and the cylinder head 36a. A release of pressurefrom this area may be effected when the tubing T1 is lifted and the port4% is registered with a release port 440 provided in the tubular supportor mandrel 25a of the packer B.

To permit pressuring up through the second tubing string, a tubularconduit 50a extending through the packer assembly B and forming acontinuation of the second tubing string T2 is formed with a port 5921.This port is adapted to register with a second angular passage 5642having a check valve 57a therein.

The packers C and B are not only connected by reason of the first tubingstring Tl but are also connected by the tubular conductor formed by thesections TZ-a and T2-b (FIGURE C). As previously explained, the sectionsTZ-a and T2-b are joined together through a union 13, such union beingnecessary in order that the tubular conductor formed by the sections maybe made up at the same time that the tubing T1 is connected to thepackers B and C. As has been noted, it is desirable to lower packers Band C by means of the first tubing string '11 and it is also desirablethat the sections T2-a and T2-b of the second tubing string be in placebetween these two packers. The provision of the union 13 makes itpossible to connect the pipe or conductor 50, which is part of thestring T2 and which is actually the section T2-b, to another conductor150 which actually forms the lower portion of section T2a. The conductor150 fits within the bore 47a of the intermediate packer B and has itslower end sealed oh? by suitable packing 68. It might be noted that thepipe 150 does not have a J-slot connection but is merely a sliding fitwithin bore 47a, so that it may be run into position and removedseparately from the first tubing string.

The tubular pipe or conductor Silo, which (forms a continuation oftubing T2, terminates just below the packer B and is provided with aninternal valve seat 69 (FIGURE 5E) which is adapted to receive one ofthe removable plugs E which is dropped into position when it is desiredto pressure up the tubing T2. Of course, when the plug is not in place,the lower end of tubing T2 is in communication with the area below theintermediate packer B.

The second packer B operates in substantially the same manner as theupper packer C as has been described and when pressure is appliedbetween the piston 37a and the cylinder head 36a, slips 39a are firstmoved up into gripping position and then the reacting force moves thepiston 37a downwardly to apply a downward force through the tubularsupport 25a to the upper end of the elastic pacle ing element 26a. Thiseffects a setting of the packing element and slips of the packer B. Theprovision of the special coupling 59 permits setting of the packingelement of the packer B without applying a downward stretch to thestrings T1 and T2.

As noted, the tubing T2 terminates below the intermediate packer B buttubing T1 extends downwardly through the lowermost packer A. Inreleasing the intermediate packer B, tubing T1 is rotated to the rightand disconnects the left-hand threads 61 of coupling 59. This permitsupward movement of the tubing T1 to locate the pressure port 40a inalignment with the release port 44a of packer B thereby relieving thepressure frombetween the piston 37a and the cylinder head 36a.Thereafter, the tubing T1 may be reconnected with the packer B throughthe threads 77 of coupling 59, which threads engage the threads 78 ofcoupling 79. A safety join-t G is connected below coupling 79 and ifpackers B and A can not be released at the same time, this safety jointmay be broken out to allow removal of packer B separately from the lowerpacker A.

The first tubing string T1 extends downwardly and through the lowerpacker A (FIGURE 5F) and supports said lower packer. The lower packer Ais illustrated in FIGURE 5F and generally follows the construction ofpackers B and C heretofore described. As shown in FIGURE 5F, packer Aincludes an upper body or header 2 3b, which has a tubular pipe sectionor mandrel 25b extending downwardly therefrom. An elastic pac'kingelement 26b surrounds the mandrel section 25b and below said packingelement is an expander cone 2%, which is suitably supported on ashoulder or ring 31b. Gripping slips 32b have their lower ends connectedto the upper end of the cylinder head 36b of a cylinder 3511.

A piston 37 b has connection with the lower end of the tubular sectionor mandrel 25b. The cylinder is nonrotatably connected to the piston bymeans of an index pin 42!) which rides in a slot 43b in the exterior ofthe piston. A shear pin 42:: formed on the inner end of the index pinnormally connects the cylinder in a lowered position relative to thepiston.

The tubing T1 extends entirely through the packer A, passing downwardlythrough the tubular section or mandrel 25b and projecting from the lowerend of piston 37]). The special clutch coupling 59, illustrated in FIG-URE 9, has its lower porton 74 threaded onto the extending end of thetubing string T1. The upper section 70 of the special coupling 59 hasits fingers '72 interengaged with the fingers 73 of the lower sectionand the shear pins 75 connect the parts in the position shown in FIGURE5F.

Pressure may be applied to the area between the piston 37b and the head36b of the cylinder 35b through an angular passage 38b having a checkvalve 39!) disposed therein. A port 401) is provided in the tubing T1and when a plug E is dropped into the lower end of the tubing T1, asshown in FIGURE 5G, to seat upon a shoulder within special coupling 91,pressure within the tubing "D1 is directed through port 40b past thecheck valve and into the area between piston and cylinder head.

The packing element and slips of packer A is set in the same manner asthe other packers, that is initial pressure between the piston andcylinder head, shears pin 42c allow-ing upward movement of the cylinderand results in setting of the slips 32b; upon setting of the slips, thereaction force of the pressure urges the piston 3711 downwardly to shearthe pins 75 in the special coupling 59. Thereafter, piston 37b andtubular section or mandrel 25b move downwardly to apply a force on theupper end of the elastic packing element 261). This downward movement ofthe piston is permitted without aplying any downward stretch to thetubing string T1.

In order to release the packer A, the tubing string is lifted upwardlyuntil the coupling 91 at the lower end thereof has its threads 92engaged with the internal threads 77 of the special coupling 59, afterwhich the tubing string T is again reconnected with the lower packer Ato per mit removal thereof from the well bore.

The particular construction of the check valves 39, 39a and 39b and thecheck valves 57 and 57a is subject to variation; however, a preferredform of check valve arrangement is illustrated in FIGURE 8 which showsthe check valve 3% in the lower packer. The angular passage 3817 isprovided with a lower annular seat 93 and an 11 upper annular seat 94. Aspring pressed ball 95 engages the lower seat and a spring pressed ball96 engages the upper seat. Both valves open to permit entry of pressure[fluid into the area between piston 37b and the head 36b of the cylinderbut function to prevent any reverse flow through the passage. Byproviding two ball valves, it is assured that the pressure will beproperly retained within the area between piston and cylinder head sinceif one valve leaks, the other will hold.

Any suitable type of removable plug E may be employed and, as a matterof fact, a ball valve could be dropped in lieu of the plug E to closethe lower ends of the three strings of tubing T1, T2 and T3. Byproviding a plug, it is possible to retrieve the same and to remove itby a wire line operation and one form of plug is shown in FIGURE 10.This figure illustrates the coupling 91 at the lower end of string T1and, as mentioned, this cou pling includes an annular seat 90. The plugE includes a main body 97 having sealing rings 98. The body is providedwith a cage 99 which is telescoped by a fishing neck 100. The lower endof the fishing neck. carries an inner valve 101 which has a portionsealing with the bore 97a of the body 97.

'It will be obvious that the plug, when in position as shown in FIGURE10, will close the bore of the tubing string T1 against downward flowtherethrough. When a suitable retrieving tool is engaged with theenlarged head of the fishing neck 100, the inner valve 101 is unseatedto equalize pressures across the plug and continued upward movement willremove the plug from its seat.

The use of the apparatus and the particular method of completingmultiple zone wells is illustrated in FIG- URES 1 to 4. As previouslymentioned, the first tubing string T1 has the lower packer A mountedthereon and is lowered as shown in FIGURE 1. Properly spaced on tubingT1 is packer B and after packer B is mounted, the

- section T2-a of the second tubing string T2 is placed in position..Thereafter, the uppermost packer C is connected to the first tubingstring T1 and at this time the second section TZ-b of the second stringT2 is coupled in position by the union 13. This arrangement isillustrated in FIGURE 2. The three packers are then lowered by means ofthe first string T1 with the tubular conductor formed by sections TZ-aand TZ-b extending between packers B and C and being lowered along withsaid packers.

After the packers are properly located, the upper section T2-c isindependently run into the well and its lower end is coupled by means ofthe J-slot connection lb--49 (FIGURE SE) to the upper packer seat.Finally the third string T3 is run into the well and is coupled to theupper packer through J-slot connection 52-5-3. The hanger 20 of thecontrol head D is then positioned and all three production or tubingstrings are properly supported therefrom after which the hanger isbolted in place in the usual manner on the tubing head 22. Since thetubing strings have the control valves 21 therein and since the outlet14 of the tubing head is provided with a control valve, the well iscompletely under control.

When all of the production or tubing strings are in finally landedposition in the control head equipment, none of the packers A, B or Care in set position and it is now possible to circulate or perform anywashing or other operation within the well while said well is undercomplete control. Thereafter, the packers may be selectively set in anydesired order and without causing a stretching of the productionstrings. If a plug E or closure is dropped into tubing T1 and thistubing is pressured up, all three packers maybe set simultaneously bythe same pressure. On the other hand, if it is desired to set theuppermost packer first, this may 'be done by pressuring up through thestring T3. After setting of the upper packer, pressure testing to assurethat it is properly set may be carried out, this being accomplished bycirculating downwardly through the first tubing string T1 and thenupwardly around the unset lower packers. Or, as explained, a washingoperation may be carried out to clean the well bore of mud and to washthe face of the formations. By dropping the plug into the second tubingstring T2, the intermediate packer B and the uppermost packer C can beset simultaneously and by proper circulation and pressure buildupthrough the tubings T1 and T3, the sealing efficiency of these packerscan be tested. The apparatus is extremely versatile and permits thecarrying out of any desired operations and the setting of the packers inany desired order, followed by proper testing to assure that they are inset position.

In releasing the packers, it is only necessary to rotate and raise thefirst tubing string Tl since this will relieve the trapped pressure frombetween the operating pistons and cylinders of said packers. Thereafter,strings T3 and T2 may be uncoupled and independently removed, afterwhich all packers may be removed by withdrawal of the string T1.

The provision of the safety joints F and G between the packers assuresthat if initial rotation of the first string T1 will not effect arelease of all connections between the string T1 and the respectivepackers, it is possible to first break .out the safety joint F betweenpackers B and C and to remove the upper packer C. Such removal would, ofcourse, remove the lower sections TZ-a and TZ-b of string T2 since thisstring merely has a slip joint connection with packer B. Thereafter, asuitable fishing tool or overshot may be engaged with the string T1 atthe upper safety joint and through manipulation both packers A and B maybe removed. If packer A is not disconnected from the string T1 at thistime, the second or lowermost safety joint may be uncoupled so thatpacker B can be withdrawn separately. Subsequently packer A may beremoved independently.

The use of the hydraulically set packers, which are positively actuatedby the pressure between piston and cylinder head, assures that positivesetting of the packers is obtained upon the application of pressurethrough one of the tubing strings. As noted, each packer is of the typein which the packing element is deformed by endwise compressive forceand the construction is such that stretching of the strings is avoidedwhen the packing element is moved to set position. Since the pressure istrapped in the area between the piston and cylinder, the packers can notbe released until the pressure acting upon the packers is released.Release of all packers is accomplished by manipulation of only the firstproduction string T1, whereby control is maintained through the singlestring.

Although three packers are shown as separating three separateformations, the apparatus lends itself to the use of any number ofpackers and in actual practice as many as five packers separating fiveproducing zones in a single well have been employed. Of course, in suchinstance two additional strings of tubing must be provided to conductindependent flow from each zone to the surface. Of importance from apractical standpoint is the fact that all production strings may belanded in final position in the control head equipment prior to the timethat the packers are set whereby various washing or other operations maybe carried out; the packers, being hydraulically set, may thereafter bemoved into sealing position without disturbing the production strings.

,The foregoing disclosure and description of the invention isillustrative and explanatory thereof and various changes in the size,shapes and materials, as well as in the details of the illustratedconstruction, may be made within the scope of the appended claimswithout departing from the spirit of the invention.

I claim:

1. The method of completing a multiple Zone well which includes,connecting a lower hydraulically-actuated well packer to the lower endof a first production string and lowering said packer and string apredetermined distance within the well bore, the lower end of said firstproduction string communicating with the area below the lower packer,then connecting a hydraulically-actuated intermediate well packer tosaid first production string and continuing the lowering of said firststring and packers, lowering a tubular conductor into the well andconnecting the lower end thereof to the intermediate packer to extendupwardly therefrom, the lower end of said conductor communicating withthe area between the lower and intermediate packers, thereafterconnecting an upper hydraulically-actuated packer to said firstproduction string and also coupling the upper packer to said tubularconductor, then further lowering the first production string, packersand conductor to locate said packers in final position within the Wellbore, then running the upper portion of a second production string andreleasably connecting it to the upper packer to communicate with thetubular conductor, said upper portion of the second string and thetubular conductor forming the complete second production string, runninga third production string and releasably connecting it with the upperpacker to communicate with the area between the upper and intermediatepackers, landing all production strings in final position in the wellhow, and thereafter setting all hydraulicallyactuated well packers byapplying a pressure thereto from the bores of the production strings.

2. The method as set forth in claim 1, together with the additionalsteps of maintaining the actuating pressure against the well packers tomaintain the same in set position even though they pressures in thebores of the production strings are reduced, and subsequentlymanipulating the first production string to relieve the hydraulicpressure applied to the well packers to effect a simultaneous releaseand unsetting of all packers.

3. The method of completing a multiple zone Well which includes,connecting a lower hydraulically-actuated well packer to the lower endof a first production string and lowering said packer and string apredetermined distance Within the well bore, then connecting ahydraulicallyactuated intermediate Well packer to said first productionstring and continuing lowering of the string and packers, lowering atubular conductor into the well and connecting the lower end of atubular conductor to the intermediate packer to extend upwardlytherefrom, thereafter connecting an upper hydraulically-actuated packerto said first production string and coupling said upper packer to saidconductor, then further lowering the first production string, packersand conductor. to locate said packers in final position within the wellbore, then running the upper portion of a second production string andreleasably connecting it to the upper packer to communicate with thetubular conductor so that said, upper portion and said tubular conductorforms the complete second production string, running a third productionstring and releasably connecting it with the upper packer, landing allproduction strings in final position in the well bore, setting the upperpacker by conducting pressure from the third production string to saidpacker, performing a washing operation within the well bore below theupper set packer to wash the well bore, and thereafter setting theintermediate and lower packers by conducting pressure from the firstproduction string to said packers.

4. A Well completion apparatus including, a first production string, alower well packer, releasable means releasably connecting the lower wellpacker to said production string, an upper well packer spaced upwardlyfrom the lower well packer, means releasably connecting the upper packerto said production string, the lower end of said first production stringcommunicating with the area below the lower packer, a second productionstring extending through the upper packer and having its lower endcommunicating with the area between the packers, each packer includinghydraulically-actuated means for setting the packer, means for directingfluid pressure from the first production string to thehydraulically-actuated means of the lower packer to actuate the samewhereby said lower packer may be set by pressure conducted thereto fromthe first production string, means for directing fluid pressure from thesecond production string to the hydraulically-actuated means of theupper packer to actuate the same whereby the upper packer may be setindepend ently of the lower packer, means in each packer maintainingpressure within the hydraulically-actuated means to maintain the packersin set position, the releasable means connecting the first productionstring and the well packers being releasable by a manipulation of thefirst production string whereby said first production string is movedrelative to said packers, and valve means on said first productionstring operated by such movement of said production string to releasethe pressure acting upon the hydraulically-actuated means of saidpackers to effect an unsetting of said packers.

5. A well completion apparatus as set forth inclaim 4, together withmeans for reconnecting the well packers to said first production stringafter said packers have been unset, whereby the packers may be removedfrom the well bore by means of said first production string.

6. A well completion apparatus including, a first production string, alower Well packer, releasable means releasably connecting the lower wellpacker to said production string, an upper well packer spaced upwardlyfrom the lower well packer, releasable mean-s releasably connecting theupper well packer to said production string, the lower end of said firstproduction string communicating with the area below the lower packer, asecond production string extending through the upper packer and havingits lower end communicating with the area between the packers, eachpacker including hydraulicallyactuated packer-setting means for settingthe packer, means for directing fluid pressure from the first productionstring to the hydraulically-actuated packer setting means of bothpackers to actuate said packers whereby both packers may be set bypressure conducted thereto from the first production string, meanswithin each Well packer for trapping the pressure which has been appliedto the hydraulically-actuated packer-setting means thereof to maintainthe packer in set position without the necessity of maintaining pressurein the production strings, the releasable means between the firstproduction string and the well packers being releasable by amanipulation of said first production string whereby the firstproduction string is moved relative to the set packers and valve meanson the production string operated by such movement of said productionstring to release the trapped pressure acting upon the packer-settingmeans of the packers to effect unsetting of said packers.

7. A well completion apparatus as set forth in claim 6, together withmeans for reconnecting the well packers to said first production stringafter said packers have been unset, whereby the packers may be removedfrom the well bore by means of said first production string.

8. The method of completing a multiple zone well as set forth in claim1, together with the step of conducting pressure from the firstproduction string to all three of the hydraulically-actuated packers toset said packers.

9. The method of completing a multiple zone well as set forth in claim 1together with the steps of conducting pressure from the third productionstring to the hydraulically-actuated upper packer to set the same, andconducting pressure from the first production string to thehydraulically-actuated intermediate and lower packers to set the same.

10. The method of completing a multiple zone well as set forth in claim1, together with the steps of conducting pressure from the secondproduction string to the upper and intermediate packers to set the same,and conducting pressure from the first production string to the lowerpacker to set the same.

11. A well completion apparatus including, a first production stringlowered into a well bore which traverses at least two producing Zones, apair of well packers mounted upon and releasably connected to saidstring and adapted to seal oil? the producing zones when moved to a setposition, said first production string having its lower endcommunicating with the area below the lower packer, means releasablyconnecting said well packers to said first production string, a secondproduction string extending from the surface of the well and through theupper packer with the lower end of said second production stringcommunicating with the area between the packers, the well packers beingin a retracted non-sealing position during lowering thereof to thedesired elevation within the Well bore, hydraulically-actuated means ineach packer for moving each packer to a set or sealing position, meansfor conducting fluid pressure from at least one of said productionstrings to said hydraulically-actuated means to actuate the same and setthe packers, normally closed valve means associated with thehydraulically-actuated means of each packer for trapping the actuatingfluid pressure within said hydraulically-actuated means to maintain eachpacker in set position, said valve means being opened by a manipulationof said first production string when the first production string ismoved relative to the packers to release the trapped fluid pressure andthereby release the packers from set position.

12. A well completion apparatus including, a first production stringlowered into a well bore which traverses at least two producing zones, apair of well packers mounted upon and releasably connected to saidstring and adapted to seal cit the producing zones when moved to a setposition, means releasably connecting said well packers to said firstproduction string, each packer including an elastic packing elementwhich is deformable by application of an endwise force thereto and alsoincluding hydraulically-actuated means :for applying such endwise forceto said packing element, said first production string extending throughboth packers and having its lower end in communication with the areabelow the lower packer, a second production string extending trom .thesurface and through the upper packer with the lower end of said secondproduction string communicating with the area between the packers, saidpackers being in a retracted non-sealing position during loweringthereof to the desired elevation within the well bore, means forconducting fluid pressure from at least one of said production stringsto said hydraulically-actuated means to actuate the same and set thepackers, normally closed valve means associated with saidhydraulically-actuated means of each packer for trapping the actuatingfluid pressure within said hydraulically-actuated means to maintain eachpacker in set position, said valve means being opened by .a manipulationof said first production string when the first production string ismoved relative to the packers to release the trapped fluid pressure andthereby release the packers from set position.

13. A well completion apparatus including, a first product-ion string, alower well packer mounted on and releasably connected to said string, anintermediate well packer mounted on and releasably connected to saidstring, an upper well packer mounted on and releasably connected to saidstring, means releasably connecting said well packers to said firstproduction string, a tubular conductor extending through and between theupper packer and the intermediate packer and having its lower endcommunicating with the area between the intermediate and lower packers,the first production string having its lower end communicating with thearea below the lower packer, said first production string, well packersand connecting tubular conductor being lowerable in the hole as aunitary assembly with the packer in a retracted position, an uppersection of a second production string extending upwardly from the upperpacker and having its lower portion releasably connected to the upperpacker and having its lower end communicating with the tubularconductor, said section of the second string and the tubular conductorforming the complete second production string, a third production stringhaving releasable connection with the upper packer, means communicatingthe lower end of the third production string with the area between theupper and intermediate packers, control head equipment at the surface ofthe well, means for landing all three production strings in finalposition in said control head equipment while the well packers are stillin unset position, each well packer including hydraulically-actuatedpacker-setting means for setting said packer, and means conducting fluidpressure from a production string to the hydraulically-actuatedpacker-setting means of each packer to actuate the same and eifectsetting of the packers after the control head equipment is in place onthe well head.

14. A well completion apparatus as set forth in claim 13, together withnormally closed valve means associated with the hydraulically-actuatedmeans of each packer for trapping the actuating fluid pressure withinthe hydraulically-actuated means to maintain each packer in setposition, the first production string being moved relative to thepackers to open said valve means and release the trapped pressure andthereby simultaneously release the packers from set position.

15. A well completion apparatus as set forth in claim 13, together witha safety joint connection in the first production string and locatedbetween the lower and intermediate packers, and a second safety jointconnection in said first production string and located between theintermediate and upper packers.

References Cited in the file of this patent UNITED STATES PATENTS381,013 Hoadley Apr. 10, 1888 1,523,286 Railsback Jan. 13, 19251,861,332 Wai-tz May 31, 1932 2,121,002 Baker June 21, 1938 2,791,277Ilfrey et a1. May 7, 1957 2,903,066 Brown Sept. 8, 1959

1. THE METHOD OF COMPLETING A MULTIPLE ZONE WELL WHICH INCLUDES,CONNECTING A LOWER HYDRAULICALLY-ACTUATED WELL PACKER TO THE LOWER ENDOF A FIRST PRODUCTION STRING AND LOWERING SAID PACKER AND STRING APREDETERMENED DISTANCE WITHIN THE WELL BORE, THE LOWER END OF SAID FIRSTPRODUCTION STRING COMMUNICATING WITH THE AREA BELOW THE LOWER PACKER,THEN CONNECTING A HYDRAULICALLY-ACTUATED INTERMEDIATE WELL PACKER TOSAID FIRST PRODUCTION STRING AND CONTINUING THE LOWERING OF SAID FIRSTSTRING AND PACKERS, LOWERING A TUBULAR CONDUCTOR INTO THE WELL ANDCONNECTING THE LOWER END THEREOF TO THE INTERMEDIATE PACKER TO EXTENDUPWARDLY THEREFROM, THE LOWER END OF SAID CONDUCTOR COMMUNICATING WITHTHE AREA BETWEEN THE LOWER AND INTERMEDIATE PACKERS, THEREAFTERCONNECTING AN UPPER HYDRAULICALLY-ACTUATED PACKER TO SAID FIRSTPRODUCTION STRING AND ALSO COUPLING THE UPPER PACKER TO SAID TUBULARCONDUCTOR, THEN FURTHER LOWERING THE FIRST PRODUCTION STRING, PACKERSAND CONDUCTOR TO LOCATE SAID PACKERS IN FINAL POSITION WITHIN THE WELLBORE, THEN RUNNING THE UPPER PORTION OF A SECOND PRODUCTION STRING ANDRELEASABLY CONNECTING IT TO THE UPPER PACKER TO COMMUNICATE WITH THETUBULAR CONDUCTOR, SAID UPPER PORTION OF THE SECOND STRING AND THETUBULAR CONDUCTOR FORMING THE COMPLETE SECOND PRODUCTION STRING, RUNNINGA THIRD PRODUCTION STRING AND RELEASABLY CONNECTING IT WITH THE UPPERPACKER TO COMMUNICATE WITH THE AREA BETWEEN THE UPPER AND INTERMEDIATEPACKERS, LANDING ALL PRODUCTION STRINGS IN FINAL POSITION IN THE WELLBORE, AND THEREAFTER SETTING ALL HYDRAULICALLYACTUATED WELL PACKERS BYAPPLYING A PRESSURE THERETO FROM THE BORES OF THE PRODUCTION STRINGS.